Refrigerant Compressor

ABSTRACT

A hermetically encapsulated refrigerant compressor, comprising a hermetically sealed compressor housing, in the interior of which a piston-cylinder unit works which compresses a refrigerant, whose cylinder housing ( 3 ) is sealed by means of a valve plate ( 16 ) comprising a pressure bore ( 25 ) and an intake bore ( 15 ), and an intake duct and a pressure duct are provided through which refrigerant is drawn into the intake bore ( 15 ) via a suction valve and is compressed via a pressure valve from the pressure bore ( 25 ) into the pressure duct, with a muffler ( 11 ) preferably being arranged in the intake duct. A clamping element ( 18 ) is provided which clamps the valve plate ( 16 ) at least along a section of its circumference, preferably along the entire circumference, against the cylinder housing ( 3 ).

BACKGROUND OF THE INVENTION

The present invention relates to a hermetically encapsulated refrigerantcompressor, comprising a hermetically sealed compressor housing, in theinterior of which a piston-cylinder unit works which compresses arefrigerant, whose cylinder housing is sealed by means of a valve platecomprising a pressure bore and an intake bore, and an intake duct and apressure duct is provided through which refrigerant is drawn into theintake bore via a suction valve and is compressed via a pressure valvefrom the pressure bore into the pressure duct, with a muffler preferablybeing arranged in the intake duct.

Such refrigerant compressors have long been known and are predominantlyused in refrigerators and cooling shelves. The annually produced numberis accordingly very high.

DESCRIPTION OF THE PRIOR ART

In known refrigerant compressors, the valve plate sealing the cylinderhousing is always screwed together with the cylinder housing in order toachieve the sealing of the cylinder space against the interior of thecompressor housing. In order to achieve such sealing, a defined pressingpressure is required. In order to facilitate the sealing, sealing of thecylinder clearance is often provided which is arranged between the valveplate and the cylinder housing and assumes a sealing function.

The fastening of the valve plate to the cylinder housing is usually madethrough four screws which are each arranged in the four corner regionsof the valve plate in order to achieve the most even pressing pressure.

The use of screws leads to a high amount of mounting work because on theone hand it is necessary to drill the threaded bores into the valveplate and the cylinder housing, and on the other hand it is necessary toscrew in each screw individually into the provided bores. In the case ofhigh piece numbers in which such refrigerant compressors are produced,this leads in summary to a high amount of time in production, whichagain entails high costs.

A compressor valve with a valve plate arranged on guide pillars is knownfrom DE 32 21 554 A1, which is held in position by means of a springsteel leaf and is fastened to the end of the cylinder block by means ofcap screws.

DE 38 13 539 A1 discloses an outlet valve arrangement of a hermeticrefrigerant compressor, with a leaf valve of the intake duct resting ona lid-shaped retaining part which on its part is pretensioned by aclamping element. This clamping element projects with its end parts inrecesses of the valve plate. This apparatus arrangement which is merelysuitable for preliminary mounting of the valve components requires aneven stronger pre-tensioning for fixing the retaining part, such thatthe cylinder head presses on the clamping element in the axial directionand the valve plate still requires a separate screw joint at its endsections in order to be fastened to the cylinder housing.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to avoid thisdisadvantage and to provide a refrigerant compressor of the kindmentioned above which can be mounted in a short period of time.

A further problem in known, screwed refrigerant compressors is theanharmonic, punctiform introduction of the sealing force into the valveplate.

It is also the goal of the present invention to provide a refrigerantcompressor which has a substantially more harmonic introduction of forceinto the valve plate, while simultaneously offering an at least evenlyremaining sealing effect between valve plate and cylinder housing.

This is achieved in accordance with the invention by the characterizingfeatures of claim 1.

By providing a clamping element which clamps the valve plate to thecylinder housing at least along a section of its circumference, complexmounting by means of screws is no longer required on the one hand andthere is a harmonic introduction of force into the valve plate on theother hand, thus providing secure sealing of the cylinder cavity againstthe interior of the compressor housing.

According to a preferred embodiment, the clamping element issubstantially arranged in a J-shaped manner and in the form of anannulus, and is latched with an end section on an undercut provided onthe cylinder housing, with the other end section of the clamping elementforming a first clamping leg which presses the cylinder housing againstthe valve plate.

According to the characterizing features of claims 6 and 7, a carrierelement forming the pressure valve in the form of a pressure leaf springand/or a sealing element, which both rest in a planar manner on thevalve plate, can be arranged between the clamping legs clamping thevalve plate and the valve plate.

According to the characterizing features of claim 8, the cylinderhousing comprises a shoulder in which the valve plate is sunk at leastpartly. According to one of the preferred embodiments as described inthe characterizing features of claim 9, the surface of the valve plateaverted from the piston is flush with the cylinder housing.

According to a further alternative embodiment as described in claim 10,the cylinder head is formed by the components forming the pressure ductor intake duct, and the clamping element comprises a further clampingleg, which pressure duct and intake duct press against the valve plateor into the suction or pressure bore.

According to the characterizing features of claim 11, a further clampingelement is provided in another alternative embodiment which can belatched with the clamping element and clamps the cylinder headconsisting of components forming the pressure duct or intake ductagainst the valve plate or into the intake bore and/or pressure bore.

The characterizing features of claims 12 and 13 describe alternativeembodiments of the clamping element in connection with a conventionalcylinder head in the form of a cylinder cover.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the invention by reference to embodiments isprovided below, wherein:

FIG. 1 shows a sectional view of a refrigerant converter according tothe state of the art;

FIG. 2 shows a sectional view of a unit with cylinder housing and valveplate with the clamping element in accordance with the invention, shownin the direction of arrows DD of FIG. 4;

FIG. 2 a shows a detailed view of a unit with cylinder housing and valveplate, comprising the clamping element in accordance with the invention;

FIG. 3 shows an axonometric view of the unit with cylinder housing andvalve plate according to FIG. 2;

FIG. 4 shows a top view of the unit with cylinder housing and valveplate according to FIGS. 3 and 4;

FIG. 5 shows an axonometric view of an alternative embodiment of theunit with cylinder housing and valve plate from FIGS. 2 to 4;

FIG. 6 shows a view of a further alternative unit with cylinder housingand valve plate, comprising the clamping element in accordance with theinvention;

FIG. 7 shows a partially sectional view in the direction of arrows A ofFIG. 6;

FIG. 8 shows a sectional view along the plane B of FIG. 6;

FIG. 9 shows a sectional view of an additional alternative unit withcylinder housing and valve plate, comprising the clamping element inaccordance with the invention;

FIG. 10 shows an axonometric view of another unit with cylinder housingand valve plate, comprising the clamping element in accordance with theinvention.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a sectional view through a hermetically encapsulatedrefrigerant compressor as is known from the state of the art. In theinterior of a hermetically sealing compressor housing 1, a unit withcylinder housing and valve plate plus motor and piston is heldelastically via springs 2.

The unit with cylinder housing and valve plate plus motor and pistonsubstantially consists of a cylinder housing 3 and the piston 4 whichperforms a travel movement, and a crankshaft bearing 5 which is arrangedperpendicularly to the cylinder axis 6. The crankshaft bearing 5receives a crankshaft 7 and protrudes into a centric bore 8 of rotor 9of an electromotor 10. A connecting-rod bearing 12 is situated at theupper end of the crankshaft 7, through which a connecting rod andsubsequently the piston 4 is driven. The crankshaft 7 comprises alubricating oil bore 13 and is fixed to rotor 9 in the area 14. Themuffler 11 is arranged on the cylinder head, which muffler is to reducethe developed noise to a minimum during the intake process of therefrigerant.

The cylinder housing 3 is sealed on its face side by means of a valveplate 16, which in conventional refrigerant compressors is screwedtogether with the cylinder housing. A cylinder cover 17 is arrangedadjacent to the valve plate 16 in refrigerant compressors according tothe state of the art, which cover is provided with webs 28 (see FIG. 2)on its side facing the valve plate 16, which webs form a pressure ductin combination with the side walls of the cylinder cover 17 and thevalve plate 16, through which compressed refrigerant pushed by thepiston from the cylinder housing 3 is forwarded to pressure lines 29 andis conveyed from the hermetically sealed compressor housing 1. Thecylinder cover 17 is usually also screwed together with the cylinderhousing 3, so that the cylinder cover 17, the valve plate 16 and thecylinder housing 3 are all screwed together.

It is provided for in accordance with the invention that the connectionbetween valve plate 16 and cylinder housing 3 is not made by means of ascrewed joint, but by means of clamping.

FIG. 2 shows a sectional view of a known unit with cylinder housing 3and valve plate 16, but with clamping according to the invention. Thevalve plate 16 and the cylinder cover 17 jointly delimit a pressureduct, through which compressed refrigerant is conveyed, namely via apressure bore 25 and a pressure valve 33 into the pressure duct andfurther into the pressure line 29. The intake bore is not visible inthis view.

In contrast to the unit with cylinder housing 3 and valve plate 16 whichis shown in FIG. 1 and in which the cylinder cover 17 is screwedtogether with the valve plate 16 and the latter with the cylinderhousing 3 (the screws are not shown in FIG. 1), the valve plate 16 istightly clamped by means of a clamping element 18 onto cylinder housing3 in the unit with cylinder housing 3 and valve plate 16 as is shown inFIG. 2.

For this purpose the cylinder housing 3 comprises an undercut 19 whichcan be latched together with an end section of the clamping element 18.The clamping element 18 itself comprises a first clamping leg 18 a thatclamps the valve plate 16 along its entire circumference against thecylinder housing 3 which for this purpose comprises a shoulder 27 inwhich the valve plate 16 is sunk at least partly but preferablyentirely, as a result of which a centering of the valve plate isachieved simultaneously. Clamping occurs along a contact edge of theclamping leg 18 a which has a circular, closed form, like the valveplate 16. It is obvious to the person skilled in the art however thatthe shape of the contact edge which finally causes the clamping of thevalve plate 16 can be chosen at will. The clamping element 18 itself canalso be chosen at will as long as it is ensured that clamping of thevalve plate 16 against the cylinder housing 3 occurs with sufficientclamping force. Sufficient clamping force is ensured when it seals thecylinder cavity 20 against the interior of the compressor housing 1enclosing the cylinder housing 3. This is achieved in practice byclamping along the circumference of the valve plate 16, with clampingalong the entire circumference not being mandatory in accordance withthe invention and it may be sufficient, depending on the clamping force,to clamp merely one section of the circumference of the valve plate 16by means of the clamping legs 18 a. The important aspect is however thatclamping occurs along the circumference, i.e. in the circumferentialregion of the valve plate 16. In order to improve the sealing effect, acylinder clearance seal 21 is provided in many cases.

Since the clamping element 18 is provided for clamping the valve plate16 against the cylinder housing, a further clamping element 30 isprovided in accordance with the invention which clamps the cylindercover 17 against the valve plate 16. The further clamping element 30 ishooked for this purpose into two grooves or openings 31 which areprovided on the clamping element 18 and are diametrically opposite ofeach other and traverses the cylinder cover 17 by simultaneouslyexerting a clamping force on the cylinder cover 17 in the region of theaxis of the piston bore.

FIGS. 3 and 4 show two further views of the unit with cylinder housing 3and valve plate 16 of FIG. 2. FIG. 4 shows the intake line 22 inaddition to the pressure line 29.

FIG. 5 shows an axonometric view of an alternative embodiment of theunit with cylinder housing 3 and valve plate 16 of FIGS. 2 to 4. Theclamping element 18 and the clamping element 30 are shown with anintegral configuration. The two clamping elements 18 and 30 are weldedtogether in a preferred embodiment. Moreover, the clamping element 18clamps the valve plate merely along a section of the circumference, i.e.not over the entire circumference, with the clamping force being chosenin such a way that there is sufficient sealing of the cylinder cavity 20against the interior of the compressor housing 1 which encloses thecylinder housing 3.

FIGS. 6, 7 and 8 show a further alternative embodiment of a unit withcylinder housing 3 and valve plate 16. The clamping element 18 islatched together again with an undercut 19 arranged on the cylinderhousing 3. A first clamping leg 18 a clamps the valve plate 16 along itsentire circumference-against the cylinder housing 3 which for thispurpose comprises a shoulder 27 in which the valve plate 16 is sunk atleast partly. Clamping occurs preferably again along a contact edge ofthe clamping leg 18 a.

In contrast to the unit with cylinder housing 3 and valve plate 16 asshown in FIG. 2 which comprises a conventional cylinder head in the formof a cylinder cover 17 and an intake duct (not shown in FIG. 2) fastenedto the valve plate 16, the cylinder head shown in FIGS. 6, 7 and 8consists of two components 23, 24 which are each arranged independentlyin such a way that it forms an independent flow duct for therefrigerant, with one flow duct 23 forming the pressure duct and theother flow duct 24 forming the intake duct, with the valve plate notbeing used as a sectional boundary of the pressure duct, as is the casein known refrigerant compressors according to FIG. 2. Accordingly, thepressure duct 23 is tightly connected with the pressure bore 25 providedin the valve plate 16 and the intake duct 24 is tightly connected withthe intake bore 15 which is also provided in the valve plate 16. Thecomponent 24 forming the intake duct is further connected with the knownmuffler 11.

Whereas the intake duct was arranged as a separate flow duct in knownrefrigerant compressors, the arrangement of a separate flow duct for thecompressed hot refrigerant in the form of a separate component 23 leadsto the consequence that the use of a conventional cylinder cover asdesignated with reference numeral 17 in FIG. 1 and FIG. 2 is no longernecessary. Since when using conventional cylinder covers 17 the valveplate 16 was always in direct contact with the compressed refrigerant(because it was a component of the pressure duct) on its surface avertedfrom the piston or at least was in direct contact with the componentforming the pressure duct, the compressed hot refrigerant was not onlyable to emit its heat in conventional refrigerant compressors from theinterior of the cylinder housing to the valve plate 16, but also fromthe outside, i.e. on the surface of valve plate 16 averted from thepiston.

By providing two separate components 23, 24 which in their sectiondirectly adjacent to the valve plate 16 are guided away from the same ina substantially rectangular manner, the compressed hot refrigerant canimmediately be transported away from the valve plate 16 without makingcontact with the valve plate 16 on its surface averted from the pistonor only contacting this surface merely at a small section around thepressure bore 25, so that a heat transfer from the compressed hotrefrigerant to the valve plate via said surface can be avoided. It canbe provided that the pressure valve 33 in the form of a pressure leafspring is arranged in the component 23.

An additional factor is that the two components 23, 24 can be madecompletely of plastic, so that also the heat transfer can virtually beprevented from said components to the valve plate.

In order to ensure a sufficiently tight connection between the pressureduct and the intake duct or the components 23, 24 with the intake bore15 or pressure bore 25 in valve plate 16, it is provided for inaccordance with the invention that the clamping element 18 comprises afurther clamping leg 18 b in addition to its first clamping leg 18 awhich clamps the valve plate 16 in the shoulder 27 of cylinder housing3, which further clamping leg presses the two components 23, 24 againstthe valve plate 16 or in the pressure bore 25 or intake bore 15.

FIG. 9 shows an additional alternative unit with cylinder housing 3 andvalve plate 16, with the clamping element 18 in accordance with theinvention comprising two clamping sections 18 a, 18 b. Clamping section18 b latches together with a groove 26 on the component 23 forming thepressure duct and on the component 24 forming the intake duct (notshown).

Based on the embodiments it is clear to the person skilled in the artthat the manner of the configuration of FIG. 10 shows an axonometricview of another alternative unit with cylinder housing 3 and valve plate16, comprising the clamping element 18 in accordance with the invention,but with a new head group, i.e. with a component 23 forming the pressureduct and a component 24 forming the intake duct. In contrast to the unitwith cylinder housing 3 and valve plate 16 as disclosed in FIGS. 6, 7,8, the clamping of the components 23, 24 occurs here by means of aseparate clamping element 30 which is latched into grooves or openings31 arranged on the clamping element 18.

of the cylinder head, i.e. either with cylinder cover 17, as known sofar, or instead with a head-group as described in the FIGS. 6 to 10, hasno influence on the invention, because it is the object of the inventionto clamp the valve plate 16 against the cylinder housing 3 in order toavoid the laborious screwing.

LIST OF REFERENCE NUMERALS

-   -   1. Compressor housing    -   2. Springs    -   3. Cylinder housing    -   4. Piston    -   5. Crankshaft bearing    -   6. Cylinder axis    -   7. Crankshaft    -   8. Centric bore    -   9. Rotor    -   10. Electromotor    -   11. Muffler    -   12. Connecting-rod bearing    -   13. Lubricating oil bore    -   14. Fixing area    -   15. Intake bore    -   16. Valve plate    -   17. Cylinder cover    -   18. Clamping element    -   19. Undercut    -   20. Cylinder cavity    -   21. Cylinder clearance seal    -   22. Intake line    -   23. Component forming the pressure duct    -   24. Component forming the intake duct    -   25. Pressure bore    -   26. Groove    -   27. Shoulder    -   28. Web    -   29. Pressure line    -   30. Clamping element    -   31. Groove or opening    -   32. Suction leaf spring    -   33. Pressure leaf spring    -   34. Gasket pressure side

1. A hermetically encapsulated refrigerant compressor, comprising ahermetically sealed compressor housing, in the interior of which apiston-cylinder unit works which compresses a refrigerant, whosecylinder housing (3) is sealed by means of a valve plate (16) comprisinga pressure bore (25) and an intake bore (15), and an intake duct and apressure duct are provided through which refrigerant is drawn into theintake bore (15) via a suction valve and is compressed via a pressurevalve from the pressure bore (25) into the pressure duct, with a muffler(11) preferably being arranged in the intake duct, wherein a clampingelement (18) is provided which clamps the valve plate (16) at leastalong a section of its circumference, preferably along the entirecircumference, against the cylinder housing (3).
 2. A hermeticallyencapsulated refrigerant compressor according to claim 1, wherein theclamping element (18) comprises a substantially J-shaped cross section.3. A hermetically encapsulated refrigerant compressor according to claim1, wherein the clamping element (18) is arranged in the form of anannulus.
 4. A hermetically encapsulated refrigerant compressor accordingto claim 1, wherein undercuts (19) are provided on the cylinder housing(3) which can be latched together with an end section of the clampingelement (18).
 5. A hermetically encapsulated refrigerant compressoraccording to claim 4, wherein the other end section of the clampingelement (18) forms a first clamping leg (18 a) which clamps the valveplate (16) against the cylinder housing (3).
 6. A hermeticallyencapsulated refrigerant compressor according to claim 5, wherein acarrier element forming the pressure valve (33)—preferably in the formof a pressure leaf spring—which rests in a planar manner on the valveplate (16) is arranged between the clamping legs (18 a) and the valveplate (16).
 7. A hermetically encapsulated refrigerant compressoraccording to claim 5, wherein a sealing element (34) which rests in aplanar manner on the valve plate (16) is arranged between the valveplate (16) and the clamping legs (18 a).
 8. A hermetically encapsulatedrefrigerant compressor according to claim 1, wherein the cylinderhousing comprises a shoulder (27) in which the valve plate (16) is sunkat least partly.
 9. A hermetically encapsulated refrigerant compressoraccording to claim 1, wherein the surface of the valve plate (16)averted from the piston (4) is flush with the cylinder housing (13). 10.A hermetically encapsulated refrigerant compressor according to claim 5,wherein the clamping element (18) comprises at least one furtherclamping leg (18 b) which clamps a component (23, 24) forming thepressure duct or intake duct against the valve plate (16) or in theintake bore (15) and/or the pressure bore (25).
 11. A hermeticallyencapsulated refrigerant compressor according to claim 1, wherein afurther clamping element (30) is provided which can be latched to theclamping element (18) and clamps the component (23, 24) forming thepressure duct or the intake duct against the valve plate (16) or in theintake bore (15) and/or the pressure bore (25).
 12. A hermeticallyencapsulated refrigerant compressor according to claim 5, wherein theclamping element (18) comprises at least one further clamping leg (18 b)which clamps the cylinder cover (17) against the valve plate (16).
 13. Ahermetically encapsulated refrigerant compressor according to claim 5,wherein a further clamping element (30) is provided which can be latchedto the clamping element (18) and clamps the cylinder cover (17) againstthe valve plate (16).